Communication Cost Model

• Comm Time per message= Overhead + Assist Occupancy + Network Delay + Size/Bandwidth + Contention

• = ov + oc + l + n/B + Tc

• Overhead and assist occupancy may be f(n) or not

• Each component along the way has occupancy and delay

  • Overall delay is sum of delays
  • Overall occupancy (1/bandwidth) is biggest of occupancies

• Comm Cost = frequency * (Comm time - overlap)

• General model for data transfer: applies to cache misses too

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